Unit heater



E. R. WALKER 2 SheetsSheet 1 a; as

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UNIT HEATER Filed Sept. 1, 1934 2 sheets-sheet 2 g 14 42 Ullllll': 3Z2 9/ a 42 Zinnentor v Em attorney Patented Dec. 24, 1 935 amaze PATENT OFFICE UNIT HEATER Edmund R. Walker, Buffalo, N. Y., assignor to Fedders Manufacturing Company, Inc., Buffalo, N. Y.

Application September 1, 1934, Serial No. 742,444

10 Claims. (01. 25713'l) v This invention relates to unit heaters, or devices in which air may be heated by forced circulation through a plurality of tubes containing a medium such as hot water or steam, and it has particular reference to improvements in such instrumentalities making for greater thermal efliciency and structural durability.

It has heretofore been proposed to heat the air of -ofiices, factory workrooms, auditoriums, and the like, by'means of apparatus in which hot water or steam was fed into a header or manifold for distribution through a plurality of small pipes leading to a second or collecting manifold, and room air simultaneously circulated around the spaced pipes by means of a motor driven fan, suitably mounted in a casing also receiving the steam distributing member. Such apparatus, while simple in its fundamental principles, has presented a large number of elusive practical problems. Among them may be mentioned the necessity of providing an effective apparatus at a low cost, to the end that the device may be accepted by potential users. Another problem has been the serious thermal and mechanical problem of expansion and contraction of the parts. While it is well known that metal will expand appreciably when heated, it has been difiicult to devise practical apparatus which would be self-compensating for the expansion caused by temperature changes. Another problem has been that of mounting the elements of the apparatus to avoid destructive strains occurring during use, while another obstacle has been the provision of a suitable mountingfor the motor, to eliminate vibratiorr- According to the present invention, it is proposed to meet these, and other problems, in an effective manner, by providing, in the unit heater, a number of improvements, which, while susceptible of individual use, conjointly cooperate to give a unit heater of attractive appearance, low cost, high thermal eifectiveness, and durability in use. As more specifically hereinafter described, it is proposed, among other things, to form the retaining casing or cabinet in vonepiece, and to associate therewith a split inner casing or shroud, which can be readily assembled in such manner as to secure the parts in their desired relation.

It i's-also proposed to provide a header and tube assembly in which there are a pair of spaced tanks of curvilinear cross-section, so designed as to eliminate warping or bulging tendencies caused by high steam pressures, and it is further proposed to mount this assembly in such manner as to avoid warping strains on the casing.

The invention further contemplates the provision of a motor and fan mounting which does not set up destructive vibrations in the assembly.

In connection with the heating elements, it is also proposed to make the steam conducting tubes of stream-line configuration, and to provide each separate tube with its own heat-radiating fins, which preferably extend longitudinally of ,the tube to the end that no tube will be strained or affected by the expansion occurri in any other tube, as would be the case if the fins connected a number of the tubes. It is further proposed to insure the even distribution of heating fluid to the several tubes by providinga distributing device in the upper header or tank, 15 and to form the tubes within the upper tank in such fashion as to prevent the collection of condensed moisture, while at the same time feed the tubes during operation with substantially dry steam.

Other objects and features of the invention, as

, well as the advantages to be derived from the use thereof, will be made apparent from a perusal of the following detailed description of one embodiment, illustrated in the accompanying drawings, wherein:

Fig. 1 is a top view of the heater with a portion broken away to show the interior structure;

Fig. 2 isa vertical section on the line 2--2 of Fig. 1 with the fins broken away;

Fig. 3 is a rear view of the cabinet on a reduced scale with the motor support secured thereto;

Fig. 4 is a perspective view of the fan shroud sections; Fig. 5 is an enlarged section on the line 5-5 of Fig. 1, with the heat radiating fins removed for clarity of illustration;

Fig. 6 is a section on the line 6-6 of Fig. 5;

Fig. 7 is a cross section, drawn on an enlarged scale, through a heater tube and attached fin; and

Fig. 8 is a front elevation of a section of heater tubing on a similar scale.

The unit heater shown in the drawings consists of a one piece cabinet I ll within which is mounted a heater element It and an electric motor I2 for driving a fan 13, to force air through the heater element. The cabinet l0 also contains a split partition or shroud M which encompasses the fan and directs the air to the heater ll, whence it escapes from the cabinet through louvers I 6, adjustably secured to the cabinet.

The cabinet I 0 is a rectilinear structure formed of a single sheet of metal to provide upper and lower walls I8 and 19 respectively, and side walls 28 terminating at each extremity in flanges 29 which are secured to the side flanges 24 of the cabinet by screws 3|. These members serve as deflectors for the heated air escaping from the cabinet, and they may be adjusted from a closed position, with their free extremities adjacent the.

guard flanges 25, to any desired angle.

The space within the cabinet is divided into a heater compartment 33 and a motor compartment 34 by the partition |4. This member, as best shown in Fig. 4, is formed of two similar sections 35 and 36 which are separately inserted through the rear opening of the cabinet and secured when properly positioned. The section 35 is formed with a vertical wall 31 having a semicircular opening 46 from which wall projects upper and lower flanges 38 and 39, and a side flange 4|, the adjacent corners of which are connected by angle members 42 and 43. The upper flange 38 and the adjacent portion of the wall 31 are bent inwardly to provide a notch 44 in the upper corner of the structure for purposes which will be hereinafter apparent.

The section 36 is similarly constructed, having a vertical wall 46 formed with a semi-circular opening 41 adapted to form a complete circle with the opening 40 upon assembly. It is also formed with upper and lower flanges 48 and 49 and a side flange 5| connected by angle members 42 and 43. I

Both sections of the partition H are formed with spaced and aligned pairs of apertures'52 disposed in the flanges thereof. These apertures are utilized to receive sections of resilient tape 53 which are threaded through the apertures as indicated in Fig. 4. When the sections are assembled in the cabinet, the tape 53 spaces the flanges from the adjacent walls of the cabinet, and it serves to prevent vibration or rattling.

The sections 35 and 36 are provided with lugs 55, 56 and 51, 58, respectively. These lugs contain holes for receiving bolts 59 (Fig. 3) which connect the sections subsequent to their insertion in the cabinet. To permit assembly with the cabinet, as hereinafter described, the upper and lower flanges oi. the sections contain notches 56 at their meeting edges and are formed with clearance holes 66 spaced from the notches. The lower flanges additionally carry nuts 54 welded in position over each clearance hole 60.

i The heater element is mounted in the heater chamber 33, and it consists generally of upper and lowertanks 6| and 62 connected by a plurality of vertically disposed tubes 63. The tanks are similar in construction, each being formed of a tank casting 64 (Figs. -5 and 6) having a rectilinear open face 65 defining a large chamber 66. The wall 61 of the chamber is semi-elliptical in cross-section and it is formed with a central boss 68 which contains a pipe tap 19 of large diameter. Smaller bosses 1| are also formed on the rear of the wall 61 and they are equally spaced from the central boss 68.

In the upper tank casting 64, the small bosses 1| are each formed with a tapped hole 12, while in the lower casting the bosses are each provided with a drilled hole 13.

A header or tube plate 15 forms the remaining part of each tank, and it is a stamping having a wall of a semi-elliptical cross section and formed with a peripheral flange 16 for engaging over the periphery of the tank casting face 65, to which it is subsequently brazed to provide a I fluid-tight joint. The plate 15 may be formed with two or more staggered rows of stamped holes 11 for receiving the ends of the tubes 63.

The tubes 63, as shown in Figs. '7 and 8, are sub- 1 stantially of an air-foil cross section, and they are disposed with their major axes in alignment with the major axis of the cabinet, and with their leading or wide edges facing the rear of the cabinet. The ends of the tubes are inserted through 15 the holes 11 of the headers, and they project within the tank chamber to approximately the medial line thereof. Certain of the tubes, as indicated by the numeral 19, have their upper ends 8| cut at an angle, in order to provide liquid :1 drainage from the lower portion of the upper tank to the lower tank. A baifle plate 82 containing holes 83 is positioned over the group of tube ends immediately below the central tapped hole in the upper tank casting.

Each tube is provided with a pair of corrugated fins 85 of the type similar to that shown in Patent No. 1,970,105. These fins are formed with saddles or depressions 86 on-their inner crests (Figs. '1 and 8) which follow the contour of the 30 side of the tube and which are secured thereto. by soldering. The fins are all disposed in paral lel relation with their surfaces in alignment with the major axis of the cabinet.

The heater element thus assembled, is the 35 flrstmember to be inserted in the cabinet, following which, the sections 35 and 36 of the partition are independently inserted and subse quently secured together as previously indicated. Bars 88 are then'inserted through slots 89 (Figs. 49 1 and 4) formed in the upper corners of the partition l4, and they are secured to the cabinet by pipe hangers 99, which extend through holes in the cabinet and holes 92 in the bars. Lock nuts 93 engaging the threaded ends of the pipe hangers secure the hanger to the cabinet, with the bars cooperating to provide a reinforcing means. Y

Both the upper tank of the heater element and the upper flange oi the partition H are 50 secured to the cabinet by a common means, the screws 95 (Fig. 5). These screws extend through suitable holes in the cabinet, spacing washers 9|, the clearance holes 66 in the partition flange, through holes 91 in the bars 88, and finally into 55 the tapped holes 12 in the upper tank casting. By this assembly the heater element H is directly supported by the pipe hangers 96, thus relieving the outer frame ill from substantially all the weight of the heating element. The hangers 98 00 may be secured to any suitable support, such as a beam, or directly to the ceiling of the roomto be heated.

The lower flanges of the partition are directly secured to the cabinet by threaded studs 99 which 05 extend through holes in the cabinet, spacing washers 9|, and into the nuts 54. Each stud is formed with an extension or pin portion |II9 which is slidablyreceived in the adjacent drilled hole 13 of the lower tank casting. 7;

A supply pipe |l| for introducing heating fluid into the upper header is inserted through a hole I93 in the cabinet and engaged in the tapped central hole 19 of the upper tank casting/ Similarly, an exhaust pipe "2 is secured to and "5 nel members I06 and I01, whose extremities are formed with lugs I08, which are secured to the flange 21 by bolts I09. A horizontally disposed plate H is secured to the channel I01 by a supporting angle iron I I I, and it in turn is bolted to the bracket N2 of the motor I2. The motor is thus suspended from the support I on a horizontal axis with its attached fan I3 disposedv within the circular opening of the partition 80.

In operation, the disposal of the tube ends in the elevated or medial position in the upper tank chamber insures that only relatively dry steam is conveyed through the tubes 63. The condensates and other heavy products fall to the bottom of the tank for drainage to the lower tank through the drainage tubes 19. The baiile plate 82, in diverting the incoming steam from a vertical to a horizontal direction of flow, not only permits the gravitational removal of the condensates, as above described, but insures a substantially uniform feed to all of the tubes, regardless of their distance from the supply pipe.

The cross sectional elliptical shape lends great physical strength to the tanks and insures them against rupture or distortion under the relatively high pressures to which they are subjected, and in so doing, the joints between the tanks and the tubes are likewise protected against shearing or bending strains.

The cabinet and the heating element are organized in such fashion that both are protected from strains caused by the expansion or contraction of the heating element. The upper tank is rigidly secured to the cabinet, but, it will be observed, the lower tank is spaced from the adjoining cabinet portion and slidably mounted on the guide pin portions I00 of the lower studs 99. Upon expansion of the heating element, the lower tank is therefore free to move upward or downward under guidance of the pin portions I00, and, as a result, no portion of the cabinet is subjected to the expansive movement of the lower tank.

It will be apparent that the device is constructed with a view to physical efliciency in the shape of the tanks and the various mounting safeguards, and that it is equally devised for great thermal efficiency in the relative disposal of the tubes"- section, and a header plate having a curvilinear.

cross section and secured to said body member to form an enclosed chamber therewith of a substantially curved cross section, each header plate being formed with a plurality of holes, tubes mounted in the holes of the header plates and thereby connecting said tanks, an input pipe communicating with one tank and an outlet pipe communicating with the remaining tank.

2. A heating element comprising a pair of elongated tanks each formed of a body member having a planar face containing an openchamber of semi-elliptical cross section, a header plate having a peripheral flange engaging over and secured to the periphery of said face and having a body portion of a semi-elliptical cross section,

said plate and body member cooperating to form 5 an enclosed chamber of a substantially elliptical cross section, each header plate being formed with a plurality of holes, tubes having their ends mounted in the holes of the header plates and thereby connecting said tanks, said tube ends extending into the chamber of the tank to substantially the medial portion thereof, an inlet passage in one tank and an outlet passage in the remaining tank. g

3. A heating element comprising an upper tank and a lower tank, tubes having their opposite ends connected to the tanks, the tube ends connected to the upper tank projecting into said tank to substantially the medial line thereof, certain of said tube ends in the upper tank being cut oif to provide a means for draining condensates from the lower portion of the upper tank, an input passage in the upper tank and an outlet passage in the lower tank.

4. A unit heater comprising a rectilinear cabinet having large openings in the front and rear walls thereof defined by peripheral internal flanges, a partition having a circular opening therein, said partition being formed of two sections each independently insertable through the opening in the rear wall of the cabinet, said sections being assembled Within the cabinet to occupy the transverse cross sectional area thereof, a heater element mounted in the cabinet on one side of the partition, a motor mounted in the cabinet on the other side of the partition, and a fan operated by the motor and disposed in the circular opening of the partition.

5. In a unit heater, a rectilinear cabinet, a heater element therein comprising an upper tank, a lower tank, and tubes'connecting said tanks, hangers secured to the cabinet, and bars secured to the hangers and to said upper tank, whereby the weight of the heater element is directly supported by the hangers.

6. In a unit heater, a rectilinear cabinet having front and rear walls formed with enlarged openings defined by peripheral flanges, a heater element mounted in the cabinet adjacent the front wall thereof, a motor support comprising a truss disposed in the opening of the rear wall and having lug portions secured to the flange of said rear wall, a plate secured to the truss, and a motor axially disposed in the cabinet and secured to the plate, said motor having a fan for directing air through the heater element.

7. In a unit heater, a rectilinear cabinet hav ing front and rear walls formed with large openings, a partition having acircular opening there= in, said partition being formed of two parts, each independently insertable through the opening in the rear wall of the cabinet, said sections being secured together and occupying the transverse cross sectional area of the cabinet, periph= eral flanges on the partition sections parallel-1:0 the adjacent walls of the cabinet, insulating tape between the flanges and the walls of the cabinet,

a heater element within said flanges, screws securing both the partition and the heater element to the cabinet, and a motor secured to the 7 cabinet, said motor having a fan disposed in the opening of said partition.

'8. In a unit heater, a rectilinear cabinet having front and rear walls formed with large openings, a partition disposed transversely in the 7 cabinet and having a peripheral flange, a heating element in the cabinet and disposed within the flanges of the partition, said heating element having upper and lower tanks, and tubes connecting the tanks, screws rigidly securing together the cabinet, upper tank and adjacent portion of the partition flange, studs extending through the bottom of the cabinet and rigidly securing the adjacent flange portion of the partition to the cabinet, said studs having projects ing pin portions and said lower tank being formed with holes for receiving said pins, whereby upon expansion or contraction oi the heating element the lower tank may move under guidance of the pin portions of said studs.

9. .A heating element comprising a pair of tanks, each tank including a body member having an open elongated chamber therein, and a sheet metal header plate secured to the body member to cover the chamber therein, said plate having a curvilinear cross section, tubes connecting the plates and extending therethrough, an inlet passage in one tank and an outlet passage in the remainlngtank.

10. A unit heater comprising a rectilinear cabinet having large openings in the front and rear walls thereof, a partition disposed transversely in the cabinet, a heating element disposed transversely in the cabinet and including an upper and :a lower tank, means securing the upper tank and adjacent portion of the partition to the cabinet, and guide pins engaged through the cabinet and rigidly seeming the partition thereto, said guide pins having portions engaging the lower tank for guided vertical movement.

EDMUND R. WALKER. 

